Pentacyclic triterpenoic acids: new chemoprotective compounds. Minireview.

Ursolic acid and oleanolic acid are pentacyclic triterpenoic acids having a similar chemical structure and are the major components of some oriental and traditional medicine herbs wildly distributed all over the world. There is a growing interest in the elucidation of the biological roles of both these triterpenoid compounds. This review summarizes the biological activities of presented triterpenoid acids (anti-inflammatory, hepatoprotective, gastroprotective, anti-ulcer, anti-HIV, cardiovascular, hypolipidemic, antiatherosclerotic and immunoregulatory effects). Our interest has been focussed especially on their anti-tumor and chemopreventive activity. Both compounds have been shown to act at various stages of tumor development, including inhibition of tumorigenesis, inhibition of tumor promotion, and induction of tumor cell differentiation. They effectively inhibit angiogenesis, invasion of tumor cells and metastasis. However, the mechanisms by which they act are poorly understood. Ursolic acid and oleanolic acid are relatively non-toxic and could be use as chemopreventive/chemoprotective agents in clinical praxis.